sprong



S. D. SPRONG.

a'mcuucc con. APPLICATION FILED mm. 22. Hub.

1 314,373. Patented Aug. 26, L919.

INVENTOR ov/1 ran BY 5 i U: ATTO NEY due to trouble in onophase,

STATES PATENT OFFICE.

- D. BPBONG, 01' 830011181. NEW YORK.

EBLCTANCE-COIL.

Application and To all whom it may concern:

Be it known that I, Snvrlnx D. Srnoso, a citizen of the United States. residing at Brooklyn. in the county of Kings and btate of New York, have invented a certain new and useful Improvement in Resistance-Coils, of which the following is a specification.

The invention is a rcactancc.

With the present large aggregations of generating capacity, it is becoming the practice to install reactance in the individual leads of the generators between generator and bus for the purpose of limiting the current in cases of short circuit. Reactance is also being used in the individual phases of outgoing feeders for the similar purpose of limiting the excess current in case of short circuit on the feeder. The general plan is to introduce an air core rcactancc in each of the several legs of the polyphasc generator or feeder. The result of this arrangement. is the permanent installation in the circuit of a fixed reactance. the reactive voltage being, of course, proportional to the current load. This is objectionable in that it introduces an element which, in the casoof the generators, causes a lowering of, the power factor by the lagging current. and in turn requiring greater excitation to overcome it. In the ease of feeders, it introdllces a reactance that ctlects the regulation of the feeder. andcauses an artificial voltage drop between terminals.

My present invention consists in introducing rcactanccs in each phase. so that. they will be mutually inductive. Under balanced loads, which is the usual condition. these will neutralize the inductive drop. each of the other; so that in event of abnormal load they will become active and perform the desired result, as hereinafter explained.

The accompanying drawing shows my invcntion in electrical diagram.

A is the generator. su plging phase current to the bus-bars B. to which are connected the feeders E, F, G, grounded at L. In each feeder is a rcactance I. J, K. the. windings of said reactances being dis posed. as indicated. in inductive relation.

lpeollleatlon of Letters Patent.

Karol: 22, 1818. Serial 110. 228,906.

balanced three-phase disturbance due to said application of this invention in the present state of the art is in cases of transimssion systems that are operated with the neutral point of the Y connection grounded. \Vhcn so grounded, an insulation breakdown on the line nearly alu'ays occurs between an individual phase and ground, in which case there is usually no spreading o trouble to adjacent phases, and so ground results in immediately operating the protective devices due either to the excess current or unbalance of the phases.

Assuming the connection in the feeder circuit of a set of balanced rcactance as escribed. it is obvious that a ground on one phase resulting in exce s: current from that phase would immediately introduce the artificial reactanre intended due to the unbalancing of the currcnts'in the mutually related reactances, therefore, the. phase having the greater current would have a pro- )ortional wuntcr-reactance voltage set. up in it which would limit thecurrcut between that iarlicular phase and ground.

I c aim:

I. In combination with a polyphasc circuit. a reactance in each phase. the said reactances being disposed in mutually inductive relation and under normal conditions being substantially balanced to neutralize. one another and under abnormal conditions due to shortcircuit of one phasebecoming unbal anceil and operating to limit the extent of short circuit.

In combination with the leads of a polyhase circuit, a reactance in each phaseasaicl rcactances ha viug windings disposed in mntuallv inductive relation and under normal conditions being substantially balanced to neutralize one another and under abnormal conditions due. to short circuit of one phase becoming unbalanced and 0 rating to limit the extent. of disturbance no to said short circuit.

In testimony whereof I have allixed my signature in presence of two witnesses.

SEVERN D. SPRONG.

A particular \Vitncsses Gnn'raunr: T. Poa'mn, Mar T. MoGaimr.

Patented Aug. 26, 1919. 

